Line array for the mix engineer

The Warehouse Sound’s Simon Meadows offers his advice on setting up and getting the best out of a flown loudspeaker system.

For a lot of us who are not system techs or system engineers, who don’t build and optimise line arrays every day, they can be difficult to fully understand – so many speakers in one place; what angles should they be set at; how should they be equalised; where should they be pointing, etc.

Line array systems should really be thought of in a different way. Most people perceive a line array as lots of speakers all hanging together because that is what they see. But really a line array is more like one big speaker made up of multiple elements and should be treated as such. It’s a bit like Lego. You use Lego bricks to build something like a truck and then you play with the truck. The bricks are no more than the building blocks of the truck, they can’t be used individually in any way like a truck until they are built into the correct shape of a truck.

In the same way line array elements (the individual speaker boxes that make up a line array) don’t really work well as speakers in their own right; they only become useful when they are put into a line array and built correctly.

With that in mind the approach to setting up and using a line array should really be in two distinct steps. Firstly we need a system engineer to design and build the line arrays to suit the venue in which they are being used, and to best amplify the content required. The content for a performance is equally as important as the venue when designing a large line array system. For example, in a venue that seats 10,000 people there will be an obvious starting point for where to put the line arrays, but we would need a completely different system to amplify the speech intelligibility of the Dalai Lama talking than we would need to provide the extreme sub bass of The Prodigy.

Once the line arrays are optimised to provide the best coverage of the audience area for the required content, we need to stop controlling the individual line array elements and use the line arrays as if they were very large point source speakers to achieve the desired result for the performance.

There needs to be a distinct separation between setting up the line arrays and using them. Once the line array setup is complete, small changes to individual line array elements have the potential to ruin the system as a whole. For example, saying ‘we could do with a bit more HF at the back’ then adding a bit of EQ to tweak the high frequencies on the top two elements of the line array (you know we’ve all done it). Without proper calculation, that change in frequency response could drastically affect the rest of the line array and result in a worse sound somewhere else in the venue.

A system engineer should design the system for the venue and plan appropriately. They will do an accurate room measurement then calculate the best placement of the line arrays to cover the audience area most effectively. This is when discussion on the content of the performance is required; information on what needs to be achieved by the system should be decided so that the system engineer can adjust their design to provide the required result. Then they will build and rig the system to the agreed design. Once the line array system is rigged they need time to correctly tune the arrays according to their calculations.

To the point

Once the engineer has finished their setup we can start to use the line arrays as if they were point sources – mixing and equalising across the system as a whole and treating it as if it were just a set of speakers on stands, resulting in a more consistent sound and better listening experience for the audience as a whole. While the sound checks and the performance are in process, the system engineer should continue to monitor the line arrays to provide us with feedback on how it is performing.

The job the system engineer does in trying to achieve the most even coverage of an audience is a very skilled one. A good system engineer will have a wealth of experience and the calculation tools to do the job well. Many system engineers will also have had training from various speaker system manufacturers in exactly how to properly set up their line array systems. We need to understand that we are all trying to achieve the best result and allow them time to give us the best system setup they can.

On smaller performances, sometimes we have to be the mix engineer and the system engineer. The process should still stay the same. First, set up the line arrays and optimise them. Then start to use them as a system. Don’t try to make changes to the line array elements once the sound checks have started.

If we can try not to be intimidated by the complexities of how a line array should be set up, and just treat them as bigger versions of normal point source speakers we can usually end up with a better sounding system. And, more importantly, by not worrying about changing and tweaking the line array elements we can have an easier and more relaxed time mixing the performance.

Simon Meadows is technical manager for The Warehouse Sound, Scotland’s largest pro-audio company, offering solutions for national broadcasters, touring firms, theatres and more.

Picture: The d&b audiotechnik system at the new Gdansk Shakespeare Theatre in Poland